Power mechanism for typewriting machines



Nov. 29, 1949 J. F. SMATHERS POWER MECHANISM FOR TYPEWRITING MACHINES Filed Feb. 6, 1947 2% I ATTORN Y Patented Nov. 29, 1949 UN [TED .QSLTAT ES PIE JPOWER MECHANISM FOR TYPEWRITING MACHINES "Application February 6, 1947; SerialNo. 726,924

(Crier-17) .6 Claims.

This invention relates to typewriting machines and more particularly I typewriters inwhich-the various mechanisms are operated by power.

The primary-object--ofthe present invention is to provide an improved power operating mechanism for typewriters.

=An object is to provide an improved power mechanism ofthe type in which the typewriter mechanisms and instrumentalities are-selectively coupled to a mainpower actuator by couplingdevices selectively controlled by'the' keys -ofthe typewriter.

object is to provide a power mechanism which is more positivein its action.

Another object is :to provide a power mechanism in which the-possibility of a misoperation is reduced to a minimum.

' An object is to provide a novel means for couplingv the instrumentalities of the typewriter, such as the type bars, to the main poweractuator. we An object is to provide a power mechanism in which the power actuator remains inactive until the coupling device is positively coupled tothe main actuator.

.Other objects of the invention willbe pointed out in the followin description and. claims and illustrated in the accompanying drawings, which disclose, by way of example, the principleof the invention and the best mode, which hasbeen contemplated, of applyingthat principle.

In the drawing:

' The drawing shows a vertical section of a power mechanism embodying the present invention.

The numeral Ill designates a type bar which is pivotally mounted at I l to swing in an arc of approximately 90 to effect an impression on the work sheet on the usual platen I2. It will be understood that there is a plurality of the type bars I and each may be provided with twoor more type characters Illa, the selection of which, in the present case, may be effected byeshifting the platen I2 in a well known way The present invention relates to the means for operatingthe type bars ill to effect printing operations and accordingly the shift mechanism by means of which the characters Illa of a type bar are selected will not be disclosed.

Associated with each type bar In is a key [3 pivoted on a cross rod Hi, the key being guidedby a suitable comb l5 and restored by a spring Hi. All of the type bars in the machine are operated by power mechanism Which includes a single cam unit ll of conventional form pivoted at :18

to a fixed part oithe machine and:cooperating. z

with the power roller l9 which rotates in the direction of the arrow.

The cam unit ii is connected by a link- 'iiila to a bell crank Zlipivoted at? l to afix-ed part of the machine. ihe bell -cra-nk- 2%?- is connected by i a link "22 to one arm 23aofan operating bail 23. When the is depressed, the-cam unit il is" rendered operable"by -the'-p0werroller l9, through ---means --described later herein; thereby causing thecamhnitl ito-be rocked in a clockwise direction, drawingdown-the link and rocking the bell-*cra'nk fii clockwise. This -bell crank through the link 22,- rocks the armil-iia in-a clock-wisedirection and causes the bail 23 to'travehupwardly and totheright.

The key lhcontrary to theusual practice when cam =units-1ike i? are employed, does not directly render the cam unit' i'i operative by the power roller. Instead the key i3 is connected by a link to a bell-crank 2 apivoted at '2'5'and connected by a link 27 to-a" release lever 23,--pivoted=on'a cross-rod 29. Pivoted on arodtii-is an arm 3| which-is connectedby a toggle spring -32 to-one arm 33a=of a coupling member 33 which is pivotedat Illb to the-type bar it]. Thereis a train of connections, such as the one just-described, foreachkey' I tin the keyboard. The normal effect of thetogglespring 2321s to tend to rock-both the" arm 3| and member 33 in acounterclockwise direction and, by pressing diagonally-upwardly to the left of the-pivot alter the type bar to both holdthetype-baragainst the. usual rest 3G andhold the right hand end of the member Si-against a channel-shaped rebound stop ban-35. counterclockwise movement ofthe arm 3tis-prevented by virtue of a pin 2m carriedvby the arm engaging a notch in apawl :ilb carried-byone-arm of the release lever Elk-a spring Sloanchored to the tail of the pawl 31b and a curved extension of thelever holding thewpawl 'iilbin the position shown in the drawing. The coupling-member 33 is provided with a hook-shaped portion 33b capable of engaging the.bail 23 under certain conditions.

:J'Extending parallel withthe bail 23 is a trip bail 36having theside arms tta pivoted at 3?. Oneof the side arms 35a is extended downwardly and is bent atf35bat an angle into the plane of a release arm 38 having a slotted connection atits lowenendtofithe upper arm of the usual release lever lid of cam unit ii; the arm 38 being pivoted at '39a to. a -bracket EEB secured to the main framework'fiil.

\When a key it is depressed thebell-crank25 and release leverit. are rocked in a clockwise direction. This, through the engagement of the notched part of the pawl 3lb with the pin 31a, rocks the arm 3! clockwise and has the efiect of Changing the point of application of the spring 32 from a line passing between the pivot point [b and the pivot II for the type bar to a line passing to the left and below the pivot I 0b. This causes the member 33 to rock clockwise and positions the hook-shaped portion 33b in front of the bail 23. At the same time this happens, the trip bail 36 will be rocked clockwise by the engagement of the hook-shaped portion 33b therewith under the stimulus of the spring 32. Motion thereby is transmitted to the arm 38 and by rotating said arm clockwise effects the release of the cam unit I! in the well known way. Thereafter the operation of the cam unit I! draws down the link 23a and operates the bail 23 in the manner described above, causing said bail 23 to travel upwardly and to the right in the drawing. The member 33 is carried along with the bail 23 and thereby propels the type bar ID to the printing point.

The release of the key i3 permits the release lever 28 to be restored to the position shown in the drawing. The movement of the member 33 upwardly and to the right gradually shifts the direction of application of the toggle spring 32 so as to tend to restore the arm 3| to the position shown in the drawing and also to tend to disengage the member 33 from the bail 23. However, the toggle spring 32 is relatively weak in comparison to the frictional force which holds the ball 23 in engagement with the lug 33b whereby, while the type bar is being propelled toward the printing position, there will be sufficient reaction force and suflicient friction between the lug 33b and the bail 23 to maintain the member 33 in engagement with the bail. When the type bar I0 is about to strike and the bail 23 reaches the end of its stroke, member 33 will be released from the bail 23 in consequence of the relieving of the pressure between the bail 23 and lug 33b by continued movement of the type bar due to inertia, permitting the spring 32 to rock the member 33 out of engagement with the bail 23 and forcing it against the longer flange of stop bar 35. Thus, during the return stroke of the type bar the spring 32 will hold the member 33 in sliding contact with the stop bar 35 until the end of the member 33 snaps back into the position shown in the drawing.

The stop bar 35 is formed as a channel shaped member with one of the flanges longer than the other to provide an abutment for the end of the member 33. This prevents rebound of the type bar since it will be observed that any tendency of the type bar I 0 to rebound will result in jamming the end of the member 33 against the longer flange of the stop bar 35.

One of the advantages of the mechanism just described over prior constructions in which the type bars are hooked to an operating bail or common actuator is that the member 33 does not render the cam unit I! effective to operate the bail 23 until the hook-shaped portion 33b has been positioned firmly in the path of the bail 23. There is no risk that the bail 23 may hit the hook-shaped portion 33b in such a manner as to cause the member 33 to glance ofi as is commonly the case of mechanisms of the snatch roll type in which the hooked member is engaged with a flute or operating bail which is continuously rotated or vibrated. Thus, the type bars and other instrumentalities of the machine are always operated positively, with the right force, and there is no possibility of incompletely operating the type bar or failing to operate it entirely.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A power mechanism for operating the instrumentalities of typewriting and other ofiice machines comprising a main driving element, a driven element having an operating connection to a instrumentality to be operated and shaped to have operating engagement with the first element; and means for engaging the driven element with the driving element including a toggle sprig connected at one end to said driven element and an arm connected to the other end of said spring and effective in one position to bias the toggle spring in a direction to hold the driven element clear of the driving element and movable to another position in which the toggle spring is biased to engage the driven element with the driving element.

2. Power operating mechanism for type bars comprising a vibratory driving element, a hookshaped driven element having an operating connection to a type bar and capable of being hooked over the driving element, an operating arm for said driven element, and spring means connecting said arm with said driven element and normally-arranged to hold the driven element unhooked from the driving element, said spring means being operative, when the arm is displaced from normal position, to hook the driven element over the driving element.

3. A power mechanism for operating the instrumentalities of typewriting and other ofiice machines comprising a main driving element, a driven element having an operating connection to an instrumentality to be operated and shaped to have driving engagement with the first element when coupled with the first element, and means for engaging the driven element with the driving element including a spring connected at one end to said driven element and a member connected to the other end of said spring and' effective in one position to bias the spring in a direction to hold the driven element clear of the driving element and movable to another position in which the spring is biased to engage the driven element with the driving element.

4. A power mechanism for operating the instrumentalities oi typewriting and other ofiicei machines comprising a main driving element, a driven element having an operating connection to an instrumentality to be operated and shaped to have driving engagement with the first element when coupled with the first element, and means for engaging the driven element with the driving element including a spring connected at one end to said driven element and a member connected to the other end of said spring and effective in one position to bias the spring in a direction to hold the driven element clear of the driving element and movable to another position in which the spring is biased to engage the driven element with the driving element, said spring being biased by movement of the driven element during the operation of said instrumentality to automatically disengage said driven element from the driving element.

5. A power mechanism for operating the instrumentalities of typewriting and other oflice machines comprising a frame having a rebound abutment, a main driving element, a driven element having an operating connection to an instrumentality to be operated and shaped to have driving engagement with the first element when coupled with the first element; and means for engaging the driven element with the driving element including a spring connected at one end to said driven element and a member connected to the other end of said spring and efiective in one position to bias the spring in a direction to hold the driven element clear of the driving element and in engagement with said abutment, said member being movable to another position in which the spring is biased to engage the driven element with the driving element, said spring being biased during the operation of said instrumentality to automatically disengage said driven element from the driving element, and being operative to re-engage said driven element with the rebound abutment during the restoration of said instrumentality.

gagement with said power actuator and, during.;

the course of the operation of said element by said actuator, automatically disengaging said element from said actuator.

JAMES F. SMATHERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,455,112 Crawley May 15, 1923 1,745,380 Quentell Feb. 4, 1930 1,945,895 Hart Feb. 6, 1934 1,955,987 Trego Apr. 24, 1934 2,158,066 Evans May 16, 1939 2,308,461 Talley Jan. 12, 1943 

